尝试将 Logger 对象转换为我自己的包装记录器时出现 ClassCastException

Question

我正在尝试通过扩展 Logger 来编写一个包装记录器类，它将记录类名、方法名、消息和错误/异常详细信息。

在下面一行得到异常

ILogger logger = 
(CustomLogger)org.apache.logging.log4j.LogManager.getLogger(name);

使用下面的 XML，有时它也会使用 SLF4J 记录器并获得 SLF4j 绑定异常。

我的 pom.xml：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.Logger</groupId>
<artifactId>WrapperLogger</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>WrapperLogger</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.2.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-logging</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-log4j2</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

================================================ =====================

log4j.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
<Appenders>
<!-- Console Appender -->
<Console name="Console" target="SYSTEM_OUT">
  <PatternLayout pattern="%d{yyyy-MMM-dd HH:mm:ss a} [%t] %M,%C, 
  %-5level %logger{36} - %msg%n" />
</Console>
<!-- File Appender -->
<File name="File" fileName="d:/app.log">
  <PatternLayout pattern="%d{yyyy-MMM-dd HH:mm:ss a} [%t] %-5level 
  %logger{36} - %msg%n" />
</File>
</Appenders>

<Loggers>
<!-- Log everything in custom package -->
<Logger name="com.boraji.tutorial.springboot" level="debug" additivity="false">
  <AppenderRef ref="Console" />
  <AppenderRef ref="File" />
</Logger>
<!-- Log everything in Spring Boot -->
<Logger name="org.springframework.boot" level="debug" additivity="false">
  <AppenderRef ref="Console" />
  <AppenderRef ref="File" />
</Logger>

<!-- Log everything in Spring Core -->
<Logger name="org.springframework.core" level="debug" additivity="false">
  <AppenderRef ref="Console" />
  <AppenderRef ref="File" />
</Logger>

<Root level="info">
  <AppenderRef ref="Console" />
  <AppenderRef ref="File" />
</Root>

Answer 1

要删除slf4j binding exceptions，您可能应该从pom.xml 中删除spring-boot-starter-logging 依赖项。

其实这个依赖已经被spring-boot-starter artificat 添加了，所以你需要像下面这样排除它-

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-log4j2</artifactId>
    </dependency>
    <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-test</artifactId>
       <scope>test</scope>
   </dependency>